The disclosure of Japanese Patent Application No. HEI 11-112223 filed on Apr. 20, 1999 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to a biological data observation system that monitors the anesthetic depth of a patient.
2. Description of the Related Art
To anesthetize a patient during a surgery, an anesthetic gas is continuously supplied to, for example, a mask placed over the patient""s mouth. If the amount of the anesthetic gas supplied is excessively small, the anesthetic depth of the patient becomes insufficient, so that the patient feels pains during the surgery. Conversely, if the anesthetic depth of a patient is excessive, the patient may fall into narcosis. Therefore, in the conventional biological data observation systems, the blood pressure of a patient is measured and displayed on a monitor. While referring to a blood pressure transition curve displayed on the monitor, an anesthesiologist adjusts the anesthetic dosage.
In general, the biological data related to movements or conditions of a heart, such as blood pressure and the like, responds to administration of an anesthetic with a delay. Therefore, monitoring only the transition of blood pressure of a patient poses a danger of a delay in coping with a change in the patient""s condition or a change in the patient""s anesthetic depth. Furthermore, the blood pressure hardly change (the change is very little) in response to a stimulus given to a patient even if the patient feels a pain. Therefore, with a system that measures only blood pressure transition, it is difficult to monitor the degree of a pain that a patient feels.
Accordingly, it is an object of the invention to provide a biological data observation system capable of observing the anesthetic depth of a patient with an increased accuracy.
To achieve the aforementioned and other objects, the invention provides a biological data observation system for monitoring an anesthetic depth of a patient, the system including a first measuring device that measures a first biological data based on an amount of perspiration of the patient. The system also includes a data processor that substantially continuously receives the data measured by the first measuring device, and that determines a transition of the data, and an indicator that externally indicates the transition of the data determined by the data processor.
Perspiration or sweating is generally divided into emotional sweating and thermal sweating. The emotional sweating is known to be greatly affected by the autonomic nervous system. In the description below, the emotional sweating and the thermal sweating are collectively referred to as xe2x80x9cperspirationxe2x80x9d or xe2x80x9csweatingxe2x80x9d. In a condition where autonomic nerves are inhibited, such as an anesthetized condition or the like, the amount of perspiration or the sweat rate is less than that in a normal condition (where the autonomic nerves are not inhibited), and increases upon a stimulus. In general, such an emotional sweat rate change is caused by control of autonomic nerve control prior to a subjective symptom. That is, perspiration is governed by autonomic nerves, and the sweat rate of a patient sensitively changes in relation to a stimulus applied to the patient, the anesthetic depth of the patient, or the like. Therefore, the system of the invention makes it possible to detect a sign of a change in the anesthetic depth based on transition of the sweat rate. Furthermore, when a stimulus is applied to an anesthetized patient in order to observe a response of the patient, the system makes it possible to observe a pain felt by the patient in terms of the sweat rate, which is quantitative data.
Thus, since the system of the invention measures the sweat rate of a patient as well as the patient""s pulse wave, the system makes it possible to more accurately observe the anesthetic depth of a patient during a surgery.
Further, by measuring transition of the patient""s pulse wave (blood pressure or the like), the system also makes it possible to observe movements or conditions of the patient""s heart in relation to an anesthetic agent.